Hi,

I'm a Mac user, but the program I use is available for PC too. It's "Cararra Studio". I design all my models in 3D first, to make sure all the internal components fit correctly, and to help me visualize how I'll build them. It's made by a company called "Eovia" at http://www.eovia.com

There's a lot more CAD stuff on my web site, including cutaway views, transparent models, and some animation. http://www.nextcraft.com

PS> I think MAX is the superior program, and am jealous.